7 April: The UN Security Council votes unanimously to authorise an international investigation into the assassination of al-Hariri. The commission is given three months to complete its work.

13 April: Karami resigns for a second time after failing to form a cabinet.

15 April: Prime minister-designate Najib Miqati forms a government.

26 April: The last Syrian soldiers leave Lebanon, ending a 29-year deployment in the country.

27 May: The UN inquiry team arrives in Beirut, led by top German prosecutor Detlev Mehlis.

19 June: The alliance led by Saad al-Hariri, son of the murdered former prime minister, wins 72 seats in the 128-member assembly after elections. The pro-Syrian Miqati resigns as prime minister. Former finance minister Fuad Siniora is named as his successor.

13 August: Mehlis confirms that his team will directly question Syrian officials as part of the investigation.

Detlev Mehlis has said he will stand down once the report is submitted

22 August: The UN team seeks an extension to its mandate.

26 August: Amid growing international criticism of its failure to answer questions, Syria declares it will cooperate with the inquiry.

30 August: Police arrest three former Lebanese security chiefs and the commander of the presidential guard at the behest of the UN inquiry team.

1 September: Lebanon's top prosecutor issues a preliminary criminal charge against the four Lebanese generals.

3 September: Syria invites Mehlis and his team to Damascus to question officials.

13 September: Lahoud denies any connection to the killing of al-Hariri.

25 September: Egypt urges the international community not to isolate Syria and says that no one should make accusations regarding al-Hariri's killing until the official report is published.

12 October: Syrian interior minister Ghazi Kanaan commits suicide, three weeks after being questioned by the inquiry. President Al-Assad again denies any Syrian involvement with the assassination.

20 October: Mehlis turns over an interim report on his findings to the UN.

21 October: The investigation team says there is "converging" evidence of both Syrian and Lebanese involvement in the killing, as Mehlis names several senior Syrian and Lebanese figures in connection with the inquiry. These include the head of Syria's powerful military intelligence.